Timed switch-control device



Filed March 3,

R. HERVE TIMED SWITCH-CONTROL DEVICE 2 Sheets-Sheet 1 Oct. 15, 1968 R.HERVE TIMED SWITCH-CONTROL DEVICE 2 Sheets'- Sheet 2 Filed March 5, 1967LOCE-S States Patent 3,406,266 TIMED SWITCH-CONTROL DEVICE RaymondHerve, La Celle-Saint-Cloud, France, assignor to La TelemecaniqueElectrique, Nanterre, Hauts-de- Seine, France, a French body corporateFiled Mar. 3, 1967, Ser. No. 620,478 Claims priority, applicatitirzzl'rance, Mar. 11, 1966,

. 8 Claims. (Cl. 200-34 ABSTRACT OF THE DISCLOSURE Contact devices areknown in which timing of the return motion of an element which operatesthe contacts of the device may be effected pneumatically through theagency of a slow change in volume of a timer chamber one wall of whichis a diaphragm associated with a central valve, the chambercommunicating with an external space through a controllable airthrottle.

The air throttle may consist of a needle valve or a passage containingcompacted fibrous material.

It has also been proposed that the air throttle might be constituted byavalve having two flat discs resiliently urged into contact with oneanother, and one of which discs possesses on that of its faces oppositethe other a fine groove which is closed off by the other disc. The otherdisc has apertures which communicate with the passage thus formed, sothat, in accordance with the relative position of the discs, a greateror lesser length of the groove is utilised. Thus, the flow of air fromthe cxteriorto the chamber and vice versa, is throttled and this altersthe changes in the volume of the said chamber.

In known embodiments of a timer device which employs a disc valvearrangement, the different component elements are coaxiallysuperimposedupon one another, but this complicates production.

In the case of the simplest of these devices, the contactoperatingelement is directly connected to the diaphragm and the timer chambercommunicates on the one hand through the valve and on the'other throughthe capillary passage (or other air throttling device), directly withthe atmosphere.

This embodiment has certain drawbacks:

The precision and reliability of operation are dependent upon the airwhich flows through the capillary passage being completely free of dust.This result can be achieved by providing a filter. However, in the knownembodiment, since a fresh quantity of atmospheric air is fed to thedevice ateach operation, the risk of the filter becoming choked is high.

Devices are also known in which the diaphragm separ-ates two virtuallyclosed chambers, air flowing from one to the other in one directionthrough a central valve of the diaphragm and in the other through acapillary passage. A device of this form which, in efliect, uses air inclosed circuit is advantageous from the point of view of functionalreliability.

Finally, a timed switch control device is known, in which the airthrottle is situated laterally in relation to the diaphragm andcommunicates with the chambers through passages which are radiallydisposed in relation to the diaphragm.

The present invention relates to a timed switch control device, with atimer chamber in simple design and great reliability.

In accordance with the invention, the body of the I timer device is amoulded component which has a cavity closed off by a diaphragm andconstituting the timer chamher, and two further cavities, the second ofwhich at least partially envelopes the first, the first of the twofurther cavities being closed off by a filter and the second by a sealedwall, the timer chamber and the first of the further cavitiescommunicating with one another through the medium of an air throttle andpassages formed in the moulded component, whilst the second of thefurther cavities communicates through narrow passages, likewise formedin the moulded component, with the space located at the external side ofthe diaphragm.

Preferably, this latter space is a compartment containing the contactsthemselves, which compartment communicates with the atmosphere through anarrow passage.

In addition, the air throttle will, advantageously, be a disc valvearrangement, the seating for which is created in one face of the mouldedcomponent, normal to the diaphragm, the passages linking this valve withthe timer chamber and with the first cavity, being disposed radially inrelation to the centre of the diaphragm, in the moulded component.

In an embodiment of the construction just mentioned, the contactcompartment constitutes, together with the two further cavities in theswitch casing, a second chamber associated with the timer chamber, inwhich the air passing from one to the other circulates in a virtuallyclosed circuit.

Preferably, the contact operating element is a slidable push-buttonassociated with a frame which serves as a contact bridge in conjunctionwith springs whose central position, corresponding to the maximumdeflection of the spring, is unstable so that even when the movement ofthe push-button is slow, the movement of the contact bridge is rapid.

Preferably, this externally-operated push-button will be enclosed andguided between a base and a cover which, when assembled together, formbetween them the contact chamber, the base supporting the body of thetimer device and the fixed contacts, and the cover trapped between theassembly of base and body, preferably being transparent in order toenable the contacts to be inspected.

The base will preferably be in the form of a bracket so that it can beattached to a side face of an electromagnetic relay provided with acontact operating strip which is movable perpendicularly in relation tothe side face (i.e. parallel to the mounting panel of the relay) inorder to be able to operate the push-button during one or other of itsreciprocating movements.

A relay of this kind, with a moving strip, has been described, inparticular, in United States patent specification No. 3,277,410 filedAug. 31, 1964 and its Canadian equivalent No. 910,585 filed Aug. 28,1964.

The ensuing description is of an example of the invention and relates tothe accompanying drawings of which:

FIGURE 1 is a side elevation of a timed contact device embodying theinvention,

FIGURE 2 is an end elevation,

FIGURE 3 is an axial section through the device,

FIGURE 4 is a perspective view of the push-button,

FIGURE 5 is an end elevation of the device, partially cut away, from theend opposite to that of FIGURE 2,

FIGURE 6 is a view in the direction indicated by VIVI in FIGURE 1, and

FIGURE 7 is a perspective view of the cover of the compartmentcontaining electric contacts, the cover being s'hown'tipside down. i a Vaxially, this push-button having, as FIGURE 1 shows, a

part E which projects externally. In order to enable the contacts to beinspected, the cover is, advantageously, made of a transparent material.

' The base A and the body B are assembled together by means of threebolts 60 the heads and shanks of which are contained in passages 61(FIGURE produced during moulding of the timer body B.

The cover D has a shoulder 62 which, when the cover has been assembledon the base A, is underneath the top face of the timer body B so thatthe cover cannot be released and is attached in sealed fashion at itsedges, to the base A.

A device embodying the invention is designed to be associated with anykind of mechanism capable of applying a pressure to the tip E in orderto trigger the switch timer system. In particular, the device may beattached to one of the ends of an electromagnetic relay F such asdescribed for example in the specifications mentioned above. A relay ofthis kind has a contact-carrying strip G, schematically illustrated inFIGURE 1, which is capable of reciprocation parallel to the mountingpanel to which the relay is attached (this is indicated by thedoubleheaded arrow H), and this strip cooperated with the tip E of thepush-button.

The device is held in place against the relay F by the dowel portions 2aon the face 2 of the base A, these dowel portions engaging grooves inthe side faces of the relay F, and by the bolts 1 associated with themating flanges of relay F and base A. Since the apparatus illustrated inthe figures can be attached at either end of the relay F, the strip Gcan cooperate with the push-button A either in the rest state or in theworking state, so that the set-up can be arranged to provide timedcontact operation either on opening or on closing of the relay contacts.

As FIGURE 4 indicates, the push-button E has a cruciform transversecross-section. It is guided in a T-section groove 3 in the base A, theT-section being completed by a portion 4 (see also FIGURE 7) of thecover D, to from a complete cross. This portion 4 comprises two pillars4a against which abut the faces 5 of the push-button E, whilst shoulders6 of the push-button are guided between the pillars 7 which are alsointegral with the cover D.

In the sides of the push-button two mutually opposite recesses 8 areformed into which there extend the ends of springs 9 of S-shape, whichare responsible for the movement of a frame 10 provided on each of itsfaces with contacts 11 which move between pairs of fixed contacts 12integral with screw terminals 13 by which the apparatus is externallyconnected into circuit. The terminals 13 are fixed to the base A betweenthe moulded flanges 36 thereof.

A contact device constituted by a push-button passing through a frameacting as a contact bridge, the connection between frame and push-buttonbeing effected through S-shaped springs, is known per se. It is knownthat the springs 9 are unstable at their point of maximum deflection.Thus, when the push-button E is displaced in one direction or the other,the frame remains in contact with a pair of fixed contacts until thesprings reach their maximum deflection but as soon as the position ofthe push-button corresponding to maximum deflection is passed the frame10 moves rapidly in the opposite direction to the push-button, thuspassing from one pair of fixed contacts to the other.

The internal end E of the push-button, also of cruciform cross-section,is enlarged and rests" a'gainsf'aflat thrust plate 14 integral with arod 15 of a valve 16. Through the medium of a spring 17, the thrustplate 14, in turn, acts on a stiffened central portion 18a of adiaphragm 18, whose periphery 18b is sealed to the edge of a cavity inthe timer body B. g

The valve 16 and the diaphragm 1 8 are biased into rest positions by aspring '19 whilst the spring 17 acts in the opposite sense to urge thediaphragm 18'and a seating thereon against the valve when the pushbutton'E is not operated. The spring 19 is carried on a screw 20 which can beused toadjust the degree of compression, the screw engaging, through asealing arrangement, the centre of a hollow conical boss 21 on the timerbodyB. This boss,attached to a, wall 22 of the body, forms inconjunction with the diaphragm 18 the timer chamber 23. In thethicknessof the wall 22 are two passages 24 and 25 (see'also FIGURE 6) which openout at 24a and 25a respectively into the top face ofthe body B and at2417 and 25b respectively, on either side of the wall 22 (see alsoFIGURE 5).

The central boss 21 is surrounded by a circularwall 26, moulded in situwithin the body B, which wall defines in the body, at the side oppositeto the diaphragm, two cavities, the first of which is central and issurrounded by the other. The wall 26 contains along its free edge, agroove in which there is located an air filter 28 associated with a seal27. The central cavity closed off by the filter, thus forms acompartment 29.

The external cavity of the body B is closed off at the back, in sealedfashion, by a plate 30 which is held in place by rivets 31 (FIGURE 5)projecting from the moulded flanges and, like the passages 61, theexternal cavity is formed in situ within the body B. At its centre,plate 30 has a boss 32 of the resilient material which holds the filter28 in position. The external cavity thus formed by.the plate 30 forms acompartment 33 which communicates with the compartment containing thecontacts through two small passages 34.

The latter compartment is completed by the assembly of the cover D onthe base A, the cover, as FIGURE 7 shows, having hollow elements 35which enclose two central flanges 36 (FIGURE 1) separating the contactterminals 13.

The top face of the body B contains arecess 37 inwhich there aresituated a rubber seal 38 and a disc 39, both being prevented fromturning by the pips 40 on the edge of the recess. The seal 38 and thedisc 39 contain apertures 41 and 42 corresponding in position with thoseopen ends 24a and 25a of the passages 24, 25. The aperture 42 extends onthe top face of the disc 39 into a radial groove 43 which leads to acircular undercut 44 in the disc. On this same face, the aperture 41extends towards the exterior, in the form of an elongated groove 45.

On top of the disc 39, there is applied through the medium of a secondsealing arrangement 46, a second disc 47 which on that of its faces incontact with the disc 39, has a radial groove 48the external end ofwhich extends into a fine circular groove 49 which intersects theelongated recess 45.

The discs 39 and 47 are of a plastic material and are accurately mouldedand polished so that they can be placed in intimate contact with oneanother to provide '{an airtight seal.

The assembly constituted by the disc valve arrangement is enclosed inthe recess formed in the underside of a knob 52 and compressed by thedished spring washer 50 with which there co-operates the screw 51, thisscrew passing through the button and engaging in the body B. A toprecess in the knob, in which there is lodged the head of the screw 51,is closed by a cover 53 press-fitted into place, this cover carryingmarkings which indicate the delay time.

The device which has just been described, operates in the followingmanner:

In the rest state (the position illustrated in FIGURE 3), the tip E ofthe push-button projects externally of the device and the contact bridgeconstituted by the frame closes a circuit passing through those contacts12 and terminals 13 which are nearest the body B (FIGURE 6). The valve16 is closed by the force of the spring 17 on the diaphragm and thethrust plate 14 is forced into contact with the push-button E by thespring 19.

When the tip E of the push-button is depressed, forcing the push-buttoninwards, the intermediate thrust plate 14 moves the disc of the valve 16whilst the spring 17, which is compressed, in turn moves the diaphragmtowards the right in FIGURE 3. The air contained in the timer chamber23, which is initially compressed in accordance with the load of thespring 17, is forced through the valve towards the contact compartment.In the course of this movement, when the springs 9 pass through theirpoint of maximum deflection, the contact bridge is suddenly displacedtowards the contacts 12 and the terminals 13 which are furthest from thebody B.

As soon as the push-button is released, the valve 16 closes (this assoon as the chamber 23 has emptied) so that the diaphragm 18 tends,under the action of the spring 19, to return to its original positionand therefore the air pressure in space 23 drops. As a consequence, airis drawn through passage 25, the circular groove 44 acing as collector,the radial groove 48, a certain length of the groove 49, the recess 45and the passage 24, in order to restore to normal the air pressure inthe chamber 23. This movement of air is the slower the longer the lengthof groove 49 included in the above path. The air which enters thepassage 25, is drawn from the contact compartment, through the smallpassages 34, the compartment 33, the filter 28 and then the compartment29. In effect, therefore, it is virtually the same air which wasexpelled from the timer chamber which ultimately returns to it and thedevice thus virtually operates in closed circuit fashion.

Equilibrium with the atmospheric pressure in the assembly, is achievedby the narrow passages created by the external projection of the tip Eof the pushbutton. However, preliminary precipitation of dust which mayenter the apparatus and of dust which may arise from contact wear, iseffected in the contact compartment and air which passes through thenarrow passages 34 has consequently had the bulk of any dust removed.Subsequently this air passes through the filter 28 and this arrangementtherefore means that the chances of the groove 49 being blocked arenegligible.

During its return movement, the diaphragm picks up the thrust plate 14which in turn returns the push-button E to its original position.

When the device is associated with a relay, as illustrated in FIGURE 1,the push-button E is normally depressed and a single pair of theterminals 13 is used all in accordance with whether it is desired tohave timed opening or timed closing of the contacts.

The time delay depends upon the viscosity of the air and, consequently,upon ambient temperature so that the most that can be done is tograduate the apparatus in markings (indicated on the plate 53 oppositean index carried by the cover D) such as a succession of letters of thealphabet, which suggest a change in the delayed time without in any wayattempting to indicate the actual delay time. To this graduation,however, a zero indication can be added, corresponding to the setting ofthe button 52 to a position in which the radial groove 48 is directly incommunication with the annular collector 42 and the recess 45. In thiscircumstance, the delay is negliible.

g The embodiment which has been described above is amenable tomodification, in particular by the substitution of equivalent technicalmeans, without departing from the scope of the present invention.

What I claim is:

1. An improved switch-control device having a timer chamber which isclosed by a diaphragm associated with a contact operating element andwhich communicates with an external space through an air throttlesituated laterally in relation to the diaphragm wherein the improvementcomprises a moulded body component having a timer chamber closed 011 bythe diaphragm, two further cavities of which the second at leastpartially envelopes the first, the first closed ofi by a filter and thesecond by a sealed wall, the timer chamber and the said first cavitycommunicating with one another via an air throttle and passages in themoulded component, whilst the second cavity communicates through apassage also created in the moulded component with a space locatedoutside the timer chamber.

2. A device as claimed in claim 1 wherein the space located outside ofthe time chamber is a compartment in which electric contacts arelocated, this space being in communication with atmosphere.

3. A device as claimed in claim 1 wherein the air throttle comprises incombination a disc valve arrangement, the seating for which is formed ina face of the moulded component which is perpendicular to the diaphragm,the said passages being disposed in said moulded component radially withrespect to the centre of the said diaphragm.

4. A device as claimed in claim 2 and further comprising an operatingelement in the form of a sliding pushbutton, a frame associated with thepush-button and which acts as a contact bridge in conjunction withsprings havin an unstable central position, the push-button having a tipwhich projects outside the contact compartment.

5. A device as claimed in claim 2 wherein the compartment containing thecontacts comprises in combination a base to which there are attached thebody and the fixed contacts, and a cover, the assembly of body and basetrapping the cover in place.

6. A device as claimed in claim 5 wherein the base of the contactcompartment is in the form of a bracket to permit its attachment to alateral face of an electromagnetic relay equipped with acontact-operating strip, the strip being movable in a directionperpendicular to the lateral face.

7. A device as claimed in claim 4 wherein the pushbutton is of acruciform transverse cross-section.

8. A device as claimed in claim 5 wherein the cover constitutes inassociation with the base, a passage for the push-button, which passagehas surfaces for the guidance of the push-button.

References Cited UNITED STATES PATENTS 3,153,706 10/1964 Faffart 335-613,213,237 10/1965 Mikina et a1 335--61 3,213,333 10/1965 Mikina et al335-61 ROBERT K. SCHAEFER, Primary Examiner. H. O. JONES, AssistantExaminer.

